<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            width: 100px;
            height: 100px;
            background-color: yellow;
            /* 边框 */
            border: 1px solid #000;
        }
        /* * 为通配符，所有标签都会调用改方法 */
        *{
             /* 内减：避免添加border撑大尺寸 */
            box-sizing: border-box;
        }
        .box {
          background-color: green;
          padding: 10px 50px 80px 40px;
        }
    </style>
</head>
<body>
    <div class="box">
div
    </div>
</body>
</html>